Re: [PATCH v3] gpio: exar: set value when external pull-up or pull-down is present

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, Nov 05, 2024 at 04:39:38PM +0200, Andy Shevchenko wrote:
> On Tue, Nov 05, 2024 at 12:45:23PM +0530, Sai Kumar Cholleti wrote:
> > Setting GPIO direction = high, sometimes results in GPIO value = 0.
> > 
> > If a GPIO is pulled high, the following construction results in the
> > value being 0 when the desired value is 1:
> > 
> > $ echo "high" > /sys/class/gpio/gpio336/direction
> > $ cat /sys/class/gpio/gpio336/value
> > 0
> > 
> > Before the GPIO direction is changed from an input to an output,
> > exar_set_value() is called with value = 1, but since the GPIO is an
> > input when exar_set_value() is called, _regmap_update_bits() reads a 1
> > due to an external pull-up.  regmap_set_bits() sets force_write =
> > false, so the value (1) is not written.  When the direction is then
> > changed, the GPIO becomes an output with the value of 0 (the hardware
> > default).
> > 
> > regmap_write_bits() sets force_write = true, so the value is always
> > written by exar_set_value() and an external pull-up doesn't affect the
> > outcome of setting direction = high.
> > 
> > 
> > The same can happen when a GPIO is pulled low, but the scenario is a
> > little more complicated.
> > 
> > $ echo high > /sys/class/gpio/gpio351/direction
> > $ cat /sys/class/gpio/gpio351/value
> > 1
> > 
> > $ echo in > /sys/class/gpio/gpio351/direction
> > $ cat /sys/class/gpio/gpio351/value
> > 0
> > 
> > $ echo low > /sys/class/gpio/gpio351/direction
> > $ cat /sys/class/gpio/gpio351/value
> > 1
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Does this need to be applied, Bart?
Seems it is missed in your branches...

-- 
With Best Regards,
Andy Shevchenko